One such transmission brake was disclosed in DE 196 52 916 A1. Therewith it is possible, in an automated transmission in countershaft design, to suitably to decelerate the rotational speed of a countershaft with the gear wheels secured thereupon when, during an upshift operation for rotational speed synchronization, it is needed to reduce the rotational speed of the drive gearwheel of the higher gear. To carry out such deceleration operations, this known transmission brake has discs standing opposite to each other and non-rotatably and axially movably disposed on the end of a countershaft extending into the housing of the transmission brake or on the transmission brake housing. Moreover, in the housing of the transmission brake, one piston-cylinder arrangement is actuatable by pressure means with the piston of which the brake discs can be pressed against each other.
Even though this known transmission brake is in itself very advantageously designed, it still needs a hydraulic pneumatic system which supplies the cylinder of the piston-cylinder arrangement with the pressure needed for actuating the brake. This really is not disadvantageous when there are also components in the vehicle other than the transmission brake which have to be supplied with a hydraulic or pneumatic actuation or control pressure. But since there are also vehicles in which the transmission brake is the only device needing a hydraulic or pneumatic actuation or control pressure, its installation in such a vehicle constitutes a not inconsiderable cost factor. One basic disadvantage of fluid-controlled transmission brakes in piston-cylinder arrangements is, in addition, that they need comparatively much installation space for their added control components (such as magnetic valves) in an area of the vehicle which often is already very cramped.
With this background, the problem on which the invention is based consists in introducing a transmission brake which can be actuated without a pneumatic or hydraulic pressure system and which also requires no large installation space.
The solution of this problem results from the features of the main claim while advantageous developments and embodiments of the invention can be understood from the sub-claims.